Before electricity, central heating, and down quilts, winter in ancient China was not simply a season but a test of class.Cold was shared by everyone, but warmth was usually not.During the Han dynasty (206 BC-220), emperors used specially designed “Warm Chambers” to protect themselves from the winter cold.The walls were plastered with a mixture of mud and Sichuan peppercorns, thought to preserve heat while resisting dampness and insects; curtains and screens helped keep out draughts.These...